Thin-film solar cells and method of making

ABSTRACT

There are now provided thin-film solar cells and method of making. The devices comprise a low-cost, low thermal stability substrate with a semiconductor body deposited thereon by a deposition gas. The deposited body is treated with a conversion gas to provide a microcrystalline silicon body. The deposition gas and the conversion gas are subjected to a pulsed electromagnetic radiation to effectuate deposition and conversion.

CONTINUING APPLICATION DATA

[0001] This application is a Continuation-in-Part application ofInternational Application No. PCT/EP00/07082, filed on Jul. 25, 2000,and claiming priority from Federal Republic of Germany PatentApplication No. 199 35 046.9, filed on Jul. 26, 1999. InternationalApplication No. PCT/EP00/07082 was pending as of the filing date of thisapplication. The United States was an elected state in InternationalApplication No. PCT/EP00/07082.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates to thin-film solar cells and method ofmaking.

[0004] 2. Background Information

[0005] Photovoltaic (PV) cells are made of materials referred to assemiconductors, such as, silicon, which is currently the most commonlyused. Basically, when light strikes the cell, a certain portion of it isabsorbed within the semiconductor material. This means that the energyof the absorbed light is transferred to the semiconductor. The energyimpacts the electrons, allowing them to flow freely. PV cells also allhave one or more electric fields which act to force electrons freed bylight absorption to flow in a certain direction. This flow of electronsis a current, and by placing metal contacts on the top and bottom of thePV cell, one can draw that current off to use externally. For example,the current can power a calculator. This current, together with thecell's voltage (which is a result of its built-in electric field orfields), defines the power that the solar cell can produce.

[0006] A display screen made with TFT (thin-film transistor) technologyis a liquid crystal display (LCD), common in notebook and laptopcomputers, that has a transistor for each pixel (that is, for each ofthe tiny elements that control the illumination of your display). Havinga transistor at each pixel means that the current that triggers pixelillumination can be smaller and therefore can be switched on and offmore quickly. TFT technology is also known as active matrix displaytechnology (and contrasts with “passive matrix” which does not have atransistor at each pixel). A TFT or active matrix display is moreresponsive to change. For example, when you move your mouse across thescreen, a TFT display is fast enough to reflect the movement of themouse cursor. (With a passive matrix display, the cursor temporarilydisappears until the display can “catch up.”) Active matrix (also knownas Thin Film Transistor or thin film transistor) is a technology used inthe flat panel liquid crystal displays of notebook and laptop computers.Active matrix displays provide a more responsive image at a wider rangeof viewing angle than dual scan (passive matrix) displays.

[0007] In this context, an Si:H film is a film of silicon in whichhydrogen is incorporated. The hydrogen content is approximately 3 to20%.

[0008] Solar cells based on the semiconductor material silicon have beenknown for many years. These solar cells are usually produced from solidmonocrystalline or polycrystalline silicon, typical thicknesses of asolar cell of this type being approximately 300 to 500 μm. Thesethicknesses are required firstly in order to ensure sufficientmechanical stability and secondly to achieve absorption of the incidentsunlight which is as complete as possible. On account of the relativelylarge film thicknesses and the associated high consumption of material,and on account of the unavoidable need for a high-temperature step fordoping of the silicon wafers (T≧1000° C.), solar cells of this typeentail expensive manufacture.

[0009] As an alternative to these relatively thick silicon solar cellsdescribed above, in addition to the thin film solar cells based onamorphous Si:H (referred to below as a-Si:H), which have already beenthe subject of research for some 20 years, thin-film solar cells madefrom microcrystalline Si:H (referred to below as μc-Si:H) have in recentyears become an established subject for investigation. This cellmaterial is expected to have a similarly high efficiency to that ofmonocrystalline silicon, but to involve less expensive productionprocesses, as are also known for a-Si:H. At any rate, the use of μc-Si:His supposed to suppress the degradation in the efficiency underintensive illumination, which is inevitable when using a-Si:H. However,a number of significant points still currently stand in the way ofcommercial utilization of μc-Si:H as the functional layer in a thin-filmsolar cell. Unlike the solar cell using a-Si:H, which has a thickness ofthe photovoltaically active film of approximately 300 nm, the solar cellmade from μc-Si:H, to achieve a similarly good utilization of theincident light, must be approximately 3000 nm thick, i.e. has to bethicker by a factor of 10. Therefore, an economic process must alsoallow the deposition rate of the microcrystalline material to be higherby this factor than that achieved for a-Si:H. An inexpensive substrate,preferably window glass or even standard plastics, appears to beindispensable as a further necessary feature for commercial utilizationof the μc-Si:H. For this purpose, it is necessary to have availabledeposition methods which are compatible with the substrates, i.e.low-temperature processes (T<100° C. for plastic or T≦200 to 300° C. forglass which is provided with a transparent conductive film), and theseprocesses must moreover still achieve high film-generation rates.

[0010] According to the prior art, microcrystalline silicon (μc-Si:H)can be applied in thin films to a support material at temperatures ofgreater than approximately 200° C. using various processes. For example,it can be deposited directly from the gas phase. By way of example, thefollowing deposition methods are known: high-frequency glow dischargedeposition (HF-PECVD), electron cyclotron resonance (ECR) process,electron cyclotron wave resonance (ECWR) process, sputter deposition,hot-wire (HW) technique, microwave CVD.

[0011] Furthermore, processes are also known in which μc-Si:H isproduced by initially depositing a-Si:H from the gas phase, which isthen transformed into μc-Si:H. The transformation of a-Si:H to μc-Si:His known, for example, from the following documents.

[0012] For example, U.S. Pat. No. 5,470,619 describes the transformationof a-Si:H into μc-Si:H by means of heat treatment at a temperature of450° C. to 600° C.

[0013] U.S. Pat. No. 5,486,237 describes a temperature-inducedtransformation of a-Si:H films into μc-Si:H films at 550° C. to 650° C.over a period of 3 to 20 hours.

[0014] U.S. Pat. No. 5,344,796 describes a process for producing a thinμc-Si:H film on a glass substrate. In this process, first of all aμc-Si:H film is generated on the substrate and serves as a seed layer,then a-Si:H is deposited on this seed layer by means of a CVD process.The a-Si:H is transformed into μc-Si:H by means of a heat treatment,preferably at between 580° C. and 600° C. for a period of from 20 to 50hours.

[0015] U.S. Pat. No. 5,693,957 likewise describes the thermaltransformation of a-Si:H films into μc-Si:H films at 600° C., thetransformation of certain a-Si:H films into μc-Si:H being deliberatelyprevented by impurities formed by these a-Si:H films.

[0016] A microwave plasma CVD process for the production of a-Si:H andμc-Si:H films is described in U.S. Pat. No. 5,334,423, in which, insaturation mode, 100% of the microwave power is introduced.

[0017] Published International Application No. 93/13553 (correspondingto U.S. Pat. No. 5,231,048) describes a microwave CVD process forproducing thin semiconductor films, the process pressure lying below thePaschen minimum. A microwave CVD process with controllable biaspotential for the production of thin semiconductor films is described indocument U.S. Pat. No. 5,204,272.

[0018] The production of μc-Si:H films by means of a microwave CVDprocess is described in U.S. Pat. No. 4,891,330, in which preferably atleast 67% of hydrogen is added to the process or precursor gas in orderto assist the formation of the μc-Si:H phase.

[0019] A plasma process for the production of a μc-Si:H layer isdescribed in document Published International Application No. 97/24769(corresponding to U.S. Pat. No. 6,309,906), the precursor gas beingdiluted with hydrogen and/or argon.

[0020] Furthermore, a plasma treatment of an a-Si:H film by means of anargon plasma is described in U.S. Pat. No. 4,762,803, and by means of ahydrogen plasma in Published International Application No. 93/10555(corresponding to U.S. Pat. No. 5,387,542), in order to obtain a μc-Si:Hfilm.

[0021] European Patent No. 0 571 632 A1 (corresponding to U.S. Pat. No.5,387,542) has disclosed a plasma CVD process for producing amicrocrystalline Si film on a substrate. For this purpose, firstly athin, amorphous Si:H film is produced on the substrate byplasma-assisted CVD coating. Then, the amorphous Si:H film is subjectedto a plasma-assisted treatment using a hydrogen plasma, the amorphousSi:H film being transformed into the microcrystalline Si:H film.

[0022] Plasma-enhanced CVD coating in pulsed mode for the production ofan amorphous Si:H film on a substrate is known from U.S. Pat. No.5,618,758.

[0023] Furthermore, it is also possible to produce a μc-Si:H film byalternating deposition of a-Si:H films and subsequent treatment of thisfilm using a hydrogen plasma. This process is generally referred to inthe literature as the layer-by-layer (LBL) technique. The process bywhich the a-Si:H is transformed into μc-Si:H at atomic level has not todate been unambiguously explained (there are several models underdiscussion), but a competition process between the etching away ofdisadvantageous Si-Si bonds and hydrogen-induced restructuring of thenetwork toward the crystalline phase, which is more favorable in energyterms, seems very likely.

[0024] Parameters which provide good a-Si:H films, i.e. those which aresuitable for components, are often used for the deposition of the a-Si:Hfilm. The thicknesses of the individual films which are reported in theliterature typically lie between 1.4 nm and several 10 s of nm. Onaccount of this relatively great variation in film thickness, the resultis aftertreatment, or posttreatment, times using an H₂ plasma which liein the range from a few seconds to several minutes. The depositionprocesses used are HF-PECVD processes, in which, on account of the lowexcitation frequency, the deposition rates are relatively low.

[0025] HF-PECVD processes at most achieve maximum deposition rates (filmthickness actually deposited divided by the time required for thisdeposition) which are significantly below 10 nm/min.

[0026] The following text provides literature references which representthe prior art of μc-Si:H deposition by means of the LBL technique:

[0027] Asano, A.; Appl. Phys. Lett. 56 (1990) 533;

[0028] Jin Jang; Sung Ok Koh; Tae Gon Kim; Sung Chul Kim, Appl. Phys.Lett. 60 (1992) 2874;

[0029] Otobe, M.; Oda, S.; Jpn. J. Appl. Phys. 31 (1992) 1948;

[0030] Kyu Chang Park, Sung Yi Kim; Min Park; Jung Mok Jun; Kyung HaLee; Jin Jang; Solar Energy Materials and Solar Cells, Vol. 34 (1994),509;

[0031] Hapke, P.; Carius, R.; Finger, F.; Lambertz, A.; Vetterl, O.;Wagner H.; Material Research Society Symposium Proceedings, Vol. 452;(1997), 737.

[0032] All the processes which have been used to date for the LBLtechnique give very low effective deposition rates (1-6 nm/min), whichrestrict commercial application. Furthermore, in the LBL processes whichhave been used to date, the individual film thicknesses (1 nm to a few10 s of nm) cannot reliably be set with accuracy without a complex insitu measurement technique. This variation from the first step of theprocess is reflected in the second step. The result in particular isthat the duration of the second step (H₂ plasma treatment) cannot bedetermined with accuracy in advance. This means that the process isdependent on an inherent stability which cannot be achieved on anindustrial scale.

[0033] Measures aimed at increasing the rate, for example by increasedintroduction of power (higher plasma densities) lead to an increase inthe particle fraction in the film and therefore to a reduction inquality.

[0034] The literature and the abovementioned documents describerelatively high process temperatures (250-330° C.), which are evidentlyrequired in order to ensure sufficient film qualities (compact, i.e.dense films) and to ensure film adhesion. Therefore, thermolabilesubstrates cannot be coated.

OBJECT OF THE INVENTION

[0035] In accordance with one object of the invention there is to beprovided a solar cell having a low-cost, low thermal stabilitysubstrate.

[0036] In accordance with another object of the invention there is to beprovided a thin-film transistor having a low-cost, low thermal stabilitysubstrate.

[0037] Working on this basis, the present invention, in at least oneaspect, is also based on the object of providing a plasma CVD processand a plasma CVD device for the production of a microcrystalline Si:Hfilm on a substrate, in which the microcrystalline Si:H film is producedby treating an amorphous Si:H film using a hydrogen plasma. Theintention is to produce a high-quality microcrystalline Si:H film on asubstrate at low cost and with high deposition rates. It is to bepossible to set and regulate the film thickness and composition in acontrolled manner, and production is to take place with the minimumpossible heating of the substrate.

SUMMARY OF THE INVENTION

[0038] According to one aspect of the invention, there is provided athin-film solar cell, comprising: a transparent substrate having a firstsurface configured to receive incident light and a second surfaceopposite said first surface; a first electrode having a first surfaceand a second surface opposite said first surface; said first electrodecomprising an electrically conductive layer of a transparent conductivematerial; a microcrystalline hydrogenated silicon semiconductor body;said microcrystalline hydrogenated silicon semiconductor body having afirst surface and a second surface opposite said first surface; saidmicrocrystalline hydrogenated silicon semiconductor body being disposedwith said first surface thereof on said second surface of said firstelectrode; said microcrystalline hydrogenated silicon semiconductor bodyoriginated from a continuous-gas-flow,pulsed-electromagnetic-radiation-excited plasma, plasma-enhancedchemical vapor deposited, continuous-gas-flow,pulsed-electromagnetic-radiation-excited,hydrogen-plasma-enhanced-treated amorphous hydrogenated silicon body;said second surface of said first electrode comprising a surfaceconfigured to accept said microcrystalline hydrogenated siliconsemiconductor body; said microcrystalline hydrogenated siliconsemiconductor body comprising at least one semiconductor layer; at leastone of each said at least one semiconductor layer having a thickness offrom about one tenth of a nanometer to about fifty nanometers; a secondelectrode having a first surface and a second surface opposite saidfirst surface; said second electrode being disposed with said firstsurface thereof on said second surface of said microcrystallinehydrogenated silicon semiconductor body; a first conductor elementconnected to said first electrode; and a second conductor elementconnected to said second electrode; said first conductor element andsaid second conductor element being configured and disposed to leadelectricity from said solar cell; said substrate having a predeterminedheat stability; said predetermined heat stability being sufficientlygreat to permit manufacture of a thin-film solar cell and saidpredetermined heat stability being sufficiently low to minimize cost.

[0039] In accordance with another aspect of the invention there isprovided a thin-film transistor, comprising: a substrate having a firstsurface and a second surface opposite said first surface; amicrocrystalline hydrogenated silicon semiconductor body; saidmicrocrystalline hydrogenated silicon semiconductor body having a firstsurface and a second surface opposite said first surface; saidmicrocrystalline hydrogenated silicon semiconductor body being disposedwith said first surface thereof on said second surface of saidsubstrate; said microcrystalline hydrogenated silicon semiconductor bodyoriginated from a continuous-gas-flow,pulsed-electromagnetic-radiation-excited plasma, plasma-enhancedchemical vapor deposited, continuous-gas-flow,pulsed-electromagnetic-radiation-excited,hydrogen-plasma-enhanced-treated amorphous hydrogenated silicon body;said microcrystalline hydrogenated silicon semiconductor body comprisingat least one semiconductor layer; at least one of each said at least onesemiconductor layer having a thickness of from about one tenth of ananometer to about fifty nanometers; said microcrystalline hydrogenatedsilicon semiconductor body comprising a source layer and a drain layer;a plurality of insulating films disposed on said microcrystallinehydrogenated silicon semiconductor body; said plurality of insulatingfilms comprising a first insulating film, a second insulating film, anda third insulating film; a gate electrode disposed on said firstinsulating film; a source electrode disposed on said second insulatingfilm; a drain electrode disposed on said third insulating film; saidsubstrate comprising a predetermined heat stability; said predeterminedheat stability being sufficiently great to permit manufacture of athin-film transistor and said predetermined heat stability beingsufficiently low to minimize cost.

[0040] In accordance with one aspect of the invention there is provideda process for providing a microcrystalline hydrogenated siliconsemiconductor body on a substrate, such as, a substrate for a thin-filmsolar cell, or a substrate for a thin-film transistor, said processcomprising: providing a substrate, said substrate having a first surfaceand a second surface opposite said first surface; flowing aplasma-enhanced chemical vapor deposition gas over said second surfaceof said substrate to deposit a body of amorphous hydrogenated silicon onsaid second surface of said substrate; flowing a plasma-enhanced,hydrogen-plasma containing conversion gas over said deposited body ofamorphous hydrogenated silicon to convert said deposited body ofamorphous hydrogenated silicon into a body of microcrystallinehydrogenated silicon; said flowing of said deposition gas and saidflowing of said conversion gas comprising at least one of: (a.), (b.),(c.), and (d.): (a.) continuously flowing said plasma-enhanced chemicalvapor deposition gas over said second surface of said substrate todeposit said body of amorphous hydrogenated silicon on said secondsurface of said substrate; (b.) continuously flowing saidplasma-enhanced, hydrogen-plasma containing conversion gas over saidbody of amorphous hydrogenated silicon to convert said deposited body ofamorphous hydrogenated silicon into a body of microcrystallinehydrogenated silicon; (c.) exposing said plasma-enhanced chemical vapordeposition gas to a pulsed electromagnetic radiation with a sufficientradiation intensity to excite said plasma contained in saidplasma-enhanced chemical vapor deposition gas thus depositing saiddeposited body of amorphous hydrogenated silicon on said second surfaceof said substrate; (d.) exposing said plasma-enhanced, hydrogen-plasmaconversion gas to a pulsed electromagnetic radiation with a sufficientradiation intensity to excite said plasma contained in saidplasma-enhanced, hydrogen-plasma conversion gas to thus effectuateconversion of said amorphous hydrogenated silicon body into saiddeposited body of microcrystalline hydrogenated silicon; and said methodfurther comprising: attaching at least two electrode means to said bodyof microcrystalline hydrogenated silicon and forming one of: a thin-filmsolar cell, or a thin-film transistor.

[0041] According to one aspect of the invention, to achieve this object,there is proposed a plasma CVD process for the production of amicrocrystalline Si:H film on a substrate, comprising the followingsteps:

[0042] 1.1 plasma-enhanced CVD coating of the substrate with at leastone thin amorphous Si:H film,

[0043] 1.2 plasma-enhanced treatment of the amorphous Si:H film using ahydrogen plasma, the amorphous Si:H film being transformed into amicrocrystalline Si:H film, and

[0044] 1.3 repeating the steps 1.1 and 1.2 if necessary which ischaracterized in that the coating or the treatment is carried out with acontinuous flow of the coating gases or the treatment gases and usingpulsed electromagnetic radiation which excites the plasma.

[0045] With regard to the device, the object is achieved, according toone aspect of the invention, by the fact that a device for producing amicrocrystalline Si:H film on a substrate using a plasma CVD process isprovided, in which an amorphous Si:H film is deposited in pulse-inducedmanner on the inner surfaces of the device, in particular on the innersurfaces of the deposition chamber.

[0046] Plasma impulse CVD processes are known and are described, forexample, in Journal of the Ceramic Society of Japan, 99 (10), 894-902(1991), this document being hereby incorporated by reference as if setforth in its entirety herein. In these processes, generally with acontinuous flow of the coating gases, the electromagnetic radiationwhich excites the plasma is supplied in pulsed form, a thin film(typically of ≧0.1 nm) being deposited on the substrate on each pulse.The fact that each power pulse is followed by a pulse pause means thateven substrates which are not thermally stable can be exposed to highpowers during a pulse. This means in particular that high coating ratesare possible without imposing significant thermal loads on thesubstrate.

[0047] Therefore, the plasma CVD process according to one aspect of theinvention for the first time allows very rapid, inexpensive productionof high-quality, microcrystalline Si:H films on a substrate. The filmthickness and the composition of the Si:H film can be set and regulatedreproducibly. The film is produced with very minor heating of thesubstrate.

[0048] The amorphous Si:H film is preferably deposited in individualfilm assemblies, it being possible to produce film assemblies comprising1 to 50, particularly 1 to 5 a-Si:H monolayers per pulse.

[0049] The film thickness of a film assembly can in this case be setreproducibly. Under otherwise constant conditions, a defined filmthickness of a-Si:H is always deposited on each pulse. It is in this waypossible to set a multiple of the film thickness of a film assembly bysimply counting the number of pulses. The film thickness of a filmassembly can for this purpose be determined experimentally on a one-offbasis. In other words, there need to be only one experimentaldetermination of the film thickness of a film assembly.

[0050] With a predetermined or gettable film thickness of the a-Si:Hfilm, the pulse-induced treatment duration with the hydrogen plasma canalso easily be predetermined experimentally and therefore accuratelydefined.

[0051] After each pulse and therefore deposition of an a-Si:H filmassembly, the coating gas is preferably changed very quickly, i.e. thegas is discharged and a new coating gas is passed into the depositionchamber.

[0052] The first film layers applied to the substrate are preferablydeposited in the form of a degressive gradient with an elevated,inherent microcrystalline Si:H content. A preferred process for theproduction of a gradient film is described in German Patent No. 44 45427 C2 (corresponding to U.S. Pat. No. 5,643,638). The fact that thefirst film already has a certain amount of μc-Si:H means that thesubsequent transformation from a-Si:H to μc-Si:H is significantlyquicker and easier, since the crystalline formation is present in thefirst film layers.

[0053] This eliminates the need for further gradient films to beproduced. Since this procedure is highly time-consuming and complex,after a gradient film containing μc-Si:H has been produced once, theprocess is switched in such a way that subsequently only a-Si:H isdeposited, and this material is transformed into μc-Si:H.

[0054] Preferably, in each case a thin, amorphous Si:H film which isfrom 0.1 to 5 nm thick is deposited and is then transformed intoμc-Si:H, with a duration of a pulse of the electromagnetic radiation of≧0.1 ms and a pulse pause of the electromagnetic radiation—i.e. thepause between two pulses—of ≦200 ms being set.

[0055] The treatment time using the pulsed hydrogen plasma is preferablyset at up to 30 seconds, in particular at up to 10 seconds.

[0056] Overall, a microcrystalline Si:H film which is up to 5000 nmthick is produced on the substrate; greater thicknesses are possiblewithout any restrictions.

[0057] The PICVD process can be carried out using alternating voltagepulses with a frequency of between approximately 50 kHz and 300 GHz. Onaccount of the high coating rate and the possibility of working within arelatively broad pressure range (0.001 to approximately 10 mbar),microwave frequencies are particularly suitable; of these frequencies,the 2.45 GHz frequency is preferred as the industrial frequency, sincethe corresponding microwave components are readily available at lowcost. As a further advantage, the pulse process offers the possibilityof shaping the pulse itself, and in this way further influencingproperties of the thin film which is deposited by a single plasma pulsein terms of the film growth direction. At a pressure of 0.1-2 mbar, anexcitation frequency of 2.45 GHz, pulse durations are between 0.1 and 2ms and pulse pauses of between 5 and ≦200 ms have proven particularlysuitable for the production of the types of film according to one aspectof the invention. If the reaction times in the plasma are very short,pulse durations of 0.01 ms may be appropriate; however, the use of suchshort pulses is often restricted by equipment considerations (pulse risetime). The recommended range for the pulse amplitude cannot be statednumerically; the minimum value is that value at which the discharge canstill just be initiated with the particular coating gas and the otherprocess parameters, and the maximum value is given by the capacity ofthe particular pulse generator used.

[0058] The procedure for producing the gradient layer will as a rule besuch that the dependence of the layer properties and/or compositions onthe pulse duration, pulse amplitude and pulse pause are determined in aseries of preliminary experiments and, during the actual production ofthe gradient film, this parameter is controlled in such a way that thedesired gradient is formed in the film growth direction. The accuracywith which the gradient must be fixed beforehand depends on the demandsimposed on the layer. With the process according to one aspect of theinvention, it is possible without difficulty to vary, for example, thecomposition of the film on the substrate in the film growth directionfrom monolayer to monolayer.

[0059] A mean microwave power of 150 mW/cm³ to 1500 mW/cm³ is preferablyused.

[0060] The amorphous Si:H film is preferably deposited from a coatinggas which contains at least one Si-organic film-forming agent, thecoating gas used being a silane, in particular SiH₄ or a chlorosilane,and a process pressure in the range from 0.1 to 1 mbar being set. Evenat high deposition rates, i.e. a relatively high process pressure and ahigh pulse power, contrary to expectation no dust or powder formationwas observed in the film.

[0061] It is particularly advantageous if the coating gas is changedvery quickly after each a-Si:H film. Very rapid gas change times (<10ms) makes the process particularly economical, and it is possible toreproducibly produce μc-Si:H films of settable thickness and quality.

[0062] Hydrogen may be added to the coating gas.

[0063] The process according to one aspect of the invention ispreferably carried out in such a manner that the substrate temperaturedoes not exceed 200° C., in particular 100° C., and particularlypreferably 50° C.

[0064] According to the process according to one aspect of theinvention, it is advantageously possible to set conductivities of theμc-Si:H film of from 10⁻⁷ S/cm to 10 S/cm, the conductivities ifappropriate being adjusted by doping with foreign atoms, for example bymeans of the coating gas.

[0065] In this case, it is preferable to produce an n-doped, p-doped orundoped μc-Si:H film. Particularly for the production of thin-film solarcells, it is necessary to produce a plurality of different μc-Si:H filmson top of one another on a substrate.

[0066] The substrate used is preferably a glass, a glass ceramic or aplastic, the substrate particularly preferably being provided with atransparent, conductive film, in particular an ITO film, a doped SnO₂film or a doped ZnO film.

[0067] A μc-Si:H film on a substrate which has been produced using theprocess according to one aspect of the invention is preferably used as acomponent of a thin-film solar cell or as a component of a thin-filmtransistor (TFT).

[0068] The above-discussed embodiments of the present invention will bedescribed further hereinbelow. When the word “invention” is used in thisspecification, the word “invention” includes “inventions”, that is theplural of “invention”. By stating “invention”, the Applicants do not inany way admit that the present application does not include more thanone patentably and non-obviously distinct invention, and maintains thatthis application may include more than one patentably and non-obviouslydistinct invention. The Applicants hereby assert that the disclosure ofthis application may include more than one invention, and, in the eventthat there is more than one invention, that these inventions may bepatentable and non-obvious one with respect to the other.

BRIEF DESCRIPTION OF THE DRAWINGS

[0069] The following exemplary embodiment and the drawings are intendedto explain the invention in more detail. In the drawings:

[0070]FIG. 1A: is a cross-sectional view of a silicon solar cell;

[0071]FIG. 1B: is a cross-sectional view of a thin-film transistor;

[0072]FIG. 1: shows a layer structure comprising individual filmassemblies of Si:H on a substrate with plasma-enhanced treatment using ahydrogen plasma;

[0073]FIG. 2: shows a detailed illustration of the first film layer ofSi:H applied to a substrate in the form of a degressive gradient; and

[0074]FIG. 3: is a schematic illustration of a CVD deposition apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0075] As shown in FIG. 1A, a prior art silicon solar cell isillustrated generally as 18 and comprises a transparent insulatingsubstrate 10, a transparent electrically conductive layer 12 and asemiconductor photoelectric conversion laminate 16 composed of a p-typeamorphous silicon layer 13, an i-type amorphous silicon layer 14, ann-type amorphous silicon layer 15, and an aluminum electrode 17 actingas the back contact. This configuration is practically used as aphotoelectric conversion device capable of being produced at arelatively low cost. Such an amorphous solar cell 18 is designed so thatlight enters the solar cell through the transparent insulating substrate10 and is absorbed mainly by the i-type amorphous silicon layer 14. Anelectromotive force is generated between the two electrodes, thetransparent electrically conductive layer 12 and the aluminum electrode17, and electricity is led out of the solar cell by a conductor 20.

[0076]FIG. 1A is a copy of FIG. 1 from U.S. Pat. No. 4,808,462, issuedto Yaba, et al. on Feb. 28, 1989 and entitled, “Solar cell substrate”from which figure copy all of the reference numerals present in theoriginal figure, as it appears in U.S. Pat. No. 4,808,462 have beenremoved. U.S. Pat. No. 4,808,462 is hereby incorporated by reference asif set forth in its entirety. The reference numerals that have beenremoved from the figure for this U.S. patent, essentially reproducedherein as FIG. 1A, indicate arrangements that are well known in theprior art.

[0077]FIG. 1B shows an example of a typical basic structure of apossible thin film transistor. In the surface part of a semiconductorlayer 32 provided on an insulating substrate 30, there are provided asource layer (source region) 34 and a drain layer (drain region) 36; andon a portion of the semiconductor layer 32 between the source layer 34and the drain layer 36, on a portion of the semiconductor layer 32 atthe left side of the source layer 34, and on a portion of thesemiconductor layer 32 at the right side of the drain layer 36, thereare provided insulating layers 38, 40, and 42, respectively. Alsoprovided are a gate electrode 44 on the insulating layer 38, a sourceelectrode 46 with an electric contact with the source layer 34 and adrain electrode 48 with an electric contact with the drain layer 36,respectively.

[0078]FIG. 1B is a copy of FIG. 1 from U.S. Pat. No. 4,814,842, issuedto Nakagawa, et al. on Mar. 21, 1989 and entitled, “Thin film transistorutilizing hydrogenated polycrystalline silicon,” from which figure copyall of the reference numerals present in the original figure, as itappears in U.S. Pat. No. 4,814,842 have been removed. U.S. Pat. No.4,814,842 is hereby incorporated by reference as if set forth in itsentirety. The reference numerals that have been removed from the figurefor this U.S. patent, essentially reproduced herein as FIG. 1B, indicatearrangements that are well known in the prior art.

[0079] A device according to one aspect of the invention for theproduction of a μc-Si:H film on a substrate using a plasma CVD processwas preconditioned in such a manner that an a-Si:H film was deposited inpulse-induced manner on the inner surfaces of the deposition chamber(reactor). The deposition chamber was covered with an a-Si:H filmcomprising several 10 s of nm, preferably several 100 s of nm.

[0080] Using a typical process pressure of 0.1-1 mbar, a-Si:H films (2)were alternately deposited from a precursor gas containing silicon andhydrogen, preferably a silane, in particular monosilane (SiH₄) with orwithout hydrogen dilution as a thin film with a thickness of from 0.1 to5 nm on a substrate (1) (FIG. 1). The duration of the hydrogen plasmatreatment may be at most 30 sec, preferably 10 sec, in particular 5 sec.For the deposition of the a-Si:H film and for the subsequent treatmentof the film using the hydrogen plasma, a pulsed microwave (2.45 GHz) wasused. This pulsed microwave technique makes it possible to exactly setthe layer thickness on the basis of an accurately controlled pulsesequence (pulse duration ≧0.1 ms; pulse pause ≦200 ms) (the depositiontakes place, as it were, in monolayers). The mean microwave power coversa range from approx. 150 mW/cm³ to approximately 1500 mW/cm³. The pulsedoperation of the microwave leads on the one hand to a considerably lowerthermal load on the substrate than with a constant mean power which ispresent with continuous microwave operation, and secondly leads toconsiderably more rapid deposition of the a-Si:H film assemblies with ahigh film quality. With the aid of extremely quick gas changes, it ispossible to achieve very short individual process times, with the resultthat the effective rate, which is calculated from the quotient of theoverall film thickness to the coating time for the overall a-Si:H filmplus the time required for the hydrogen plasma treatment, at approx.10-80 nm/min is at least one order of magnitude higher than haspreviously been indicated in the literature. The substrate temperaturemay lie between 25° C. and 400° C. Contrary to expectation, therefore,it is possible to produce a compact film of good quality even at T<100°C., in particular at T<50° C., making it possible to use the processaccording to one aspect of the invention to deposit μc-Si:H films (2) inparticular even on temperature-sensitive plastic substrates (e.g. PE).

[0081]FIG. 2 shows a detailed view of the first film layer (2) which hasbeen applied to the substrate and has been deposited in the form of adegressive gradient with an elevated, inherent microcrystalline Si:Hcontent.

[0082] In this case, the film-forming agent concentration increases withincreasing time and number of pulses. The profile of the layer-formingagent concentration (concentration gradient) against the time and as afunction of the number of pulses (microwave pulse sequence) is shown onthe right in FIG. 2.

[0083] The hydrogen plasma in a preconditioned reactor produces twoimportant effects: firstly, the μc-Si:H phase is preferentially formed,and furthermore the etching effect which runs in parallel leads toremoval of undesired layers on the microwave window and the remaininginner reactor surfaces. Therefore, the hydrogen plasma has a beneficialeffect on the desired material modification in combination with acleaning action on the reactor. In this way, it is possible to introducesignificantly extended maintenance intervals, which have a beneficialeffect on industrial implementation.

[0084] Over the course of time, various proposed models for theformation of μc-Si:H have been developed. In the so-called etchingmodel, the assumption is that atomic hydrogen formed by the plasmapreferentially breaks open weak Si—Si bonds at the growing film surfaceand silicon atoms in the network are replaced, so that ultimately thecrystalline phase (stronger bonds) dominates the amorphous phase. Theso-called chemical annealing model takes account of the fact that, ifthe deposition parameters are selected appropriately, no change in filmthickness is observed during the hydrogen plasma treatment phase. In theproposed model, atomic hydrogen penetrates into a growth zone below thefilm surface, and promotes the formation of a flexible network, i.e. areorganization of the network in favor of the crystalline phase, withoutsilicon bonds being etched away.

[0085] In the process according to one aspect of the invention, theformation process of the microcrystalline Si:H phase is very probablyinfluenced by the fact that the hydrogen plasma which acts on theamorphous Si:H film which has previously been deposited effectsvirtually complete coverage of the previously deposited amorphous layer.The hydrogen coverage of the surface leads firstly, on account of thesaturation of free valencies and secondly through the provision ofrecombination energy, to a drastic increase in the surface diffusionconstant of the film-forming particles. This makes it possible for theseparticles to adopt positions which are favorable in terms of energy,leading to the formation of crystalline areas (seeds) and then tocomplete crystallization of a plurality of monolayers.

[0086] The films produced in this way are distinguished by a highcrystallinity and good saturation of the grain boundaries between theindividual crystallites. The transformation rate (a-Si:H to μc-Si:H) isconsiderably increased by the formation of seed films (mixed phase withelevated inherent μc-Si:H content) generated in the first atomic layers.According to one aspect of the invention, this is achieved by thetargeted introduction of a rate gradient. Precise control of theabovementioned gradient can only be achieved by the pulsed mode of themicrowave, since only in this way it is possible to separate fresh gasand off-gas influences on the film formation and to deliberately set gasmixtures or concentration ratios. Furthermore, the pulsed mode of themicrowave makes it possible to use high peak powers and therefore toobtain high deposition rates. The phenomenon of the quality of filmformation being reduced by the inclusion of particles is not observed.Clearly, electrostatic influences from the plasma boundary layer play asignificant role; the pulsed mode suppresses the formation of particleseven at high peak powers. Consequently, these films can be usedeconomically in electronic components, in particular in solar cells, forthe first time.

[0087]FIG. 3 shows a schematic view of an apparatus in accordance withone aspect of the invention. Thus, a substrate 52 is held on the toppart of a film forming chamber 50, or is supported in the chamber 50,and the substrate is possibly heated to be kept at a desiredtemperature. A film-forming gas is supplied through a source gas inletpipe 58 to be introduced from the bottom part into the inside of thefilm forming chamber 50. The film-forming gas is exhausted to the rightin the drawing by an exhaust pump (not shown). High-frequency power issupplied from a high-frequency power supply 56 to be introduced througha high-frequency electrode 54 into the inside of the film formingchamber 50 to decompose and excite the source gas, thereby generating aplasma.

[0088]FIG. 3 is a copy of FIG. 1 from U.S. Pat. No. 6,057,005, issued toNishimoto on May 2, 2000 and entitled, “Method of forming semiconductorthin film,” from which figure copy all of the reference numerals presentin the original figure, as it appears in U.S. Pat. No. 6,057,005 havebeen removed. U.S. Pat. No. 6,057,005 is hereby incorporated byreference as if set forth in its entirety. The reference numerals thathave been removed from the figure for this U.S. patent, essentiallyreproduced herein as FIG. 3 indicate arrangements that are well known inthe prior art.

[0089] One feature of the invention resides broadly in a plasma CVDprocess for the production of a microcrystalline Si:H film on asubstrate, comprising the following steps: plasma-enhanced CVD coatingof the substrate with at least one thin amorphous Si:H film,plasma-enhanced treatment of the amorphous Si:H film using a hydrogenplasma, the amorphous Si:H film being transformed into amicrocrystalline Si:H film, and repeating the steps if necessarycharacterized in that the coating or the treatment is carried out with acontinuous flow of the coating gases or the treatment gases and usingpulsed electromagnetic radiation which excites the plasma.

[0090] Another feature of the invention resides broadly in the process,characterized in that an amorphous Si:H film in each case comprising 1to 50 amorphous Si:H monolayers is deposited.

[0091] Yet another feature of the invention resides broadly in theprocess, characterized in that the first film layers which are appliedto the substrate are deposited in the form of a degressive gradient withan elevated, inherent microcrystalline Si:H fraction.

[0092] Still another feature of the invention resides broadly in theprocess, characterized in that a thin amorphous Si:H film which is ineach case 0.1 to 5 nm thick is deposited and transformed.

[0093] A further feature of the invention resides broadly in theprocess, characterized in that a treatment duration with the pulsedhydrogen plasma of up to 30 seconds, in particular of up to 10 seconds,is set.

[0094] Another feature of the invention resides broadly in the process,characterized in that a duration of a pulse of the electromagneticradiation of ≧0.1 ms is set.

[0095] Yet another feature of the invention resides broadly in theprocess, characterized in that a pause between two pulses of theelectromagnetic radiation of ≦200 ms is set.

[0096] Still another feature of the invention resides broadly in theprocess, characterized in that overall a microcrystalline Si:H filmwhich is up to 5000 nm thick is produced on the substrate.

[0097] A further feature of the invention resides broadly in theprocess, characterized in that the plasma is excited by means ofmicrowave radiation.

[0098] Another feature of the invention resides broadly in the process,characterized in that an excitation frequency of the magnetic radiationof 2.45 GHz is used.

[0099] Yet another feature of the invention resides broadly in theprocess, characterized in that a mean microwave power of 150 mW/cm³ to1500 mW/cm³ is used.

[0100] Still another feature of the invention resides broadly in theprocess, characterized in that the amorphous Si:H film is deposited froma coating gas which contains at least one Si-organic film-forming agent.

[0101] A further feature of the invention resides broadly in theprocess, characterized in that the coating gas used is a silane, inparticular SiH₄ or a chlorosilane.

[0102] Another feature of the invention resides broadly in the process,characterized in that hydrogen is added to the coating gas.

[0103] Yet another feature of the invention resides broadly in theprocess, characterized in that a process pressure of from 0.1 to 1 mbaris set.

[0104] Still another feature of the invention resides broadly in theprocess, characterized in that the coating gas is changed very quicklyafter each Si:H film.

[0105] A further feature of the invention resides broadly in theprocess, characterized in that the substrate temperature during theprocess does not exceed 200° C., preferably 100° C., in particular 50°C.

[0106] Another feature of the invention resides broadly in the process,characterized in that conductivities of the microcrystalline Si:H filmof from 10⁻⁷ S/cm to 10 S/cm are set.

[0107] Yet another feature of the invention resides broadly in theprocess, characterized in that a substrate made from a glass, a glassceramic or a plastic is used.

[0108] Still another feature of the invention resides broadly in theprocess, characterized in that the substrate is provided with atransparent, conductive film.

[0109] A further feature of the invention resides broadly in theprocess, characterized in that the transparent, conductive film is anITO film, a doped SnO₂ film or a doped ZnO film.

[0110] Another feature of the invention resides broadly in a device forproducing a microcrystalline Si:H film, on a substrate using the plasmaCVD process as claimed in at least one of claims 1 to 21, characterizedin that, before production of the microcrystalline Si:H film commences,an amorphous Si:H film is deposited on the inner surfaces of the device,in particular on the inner surfaces of the deposition chamber.

[0111] Yet another feature of the invention resides broadly in the useof a microcrystalline Si:H film on a substrate which has been producedas described as a component of thin-film solar cell.

[0112] Still another feature of the invention resides broadly in the useof a microcrystalline Si:H film on a substrate which has been producedas described as a component of a thin-film transistor (TFT).

[0113] One feature of the invention resides broadly in a plasma CVDprocess for the production of a microcrystalline Si:H film on asubstrate, comprising the following steps: plasma-enhanced CVD coatingof the substrate with at least one thin amorphous Si:H film,plasma-enhanced treatment of the amorphous Si:H film using a hydrogenplasma, the amorphous Si:H film being transformed into amicrocrystalline Si:H film, and repeating the steps if necessarycharacterized in that the coating or the treatment is carried out with acontinuous flow of the coating gases or the treatment gases and usingpulsed electromagnetic radiation to excite the corresponding plasma.

[0114] One feature of the invention resides broadly in a plasma chemicalvapor deposition process for the production of a microcrystallinehydrogenated silicon film or body on a substrate, comprising thefollowing steps: plasma-enhanced chemical vapor deposition coating ofthe substrate with at least one thin amorphous hydrogenated siliconfilm, plasma-enhanced treatment of the amorphous hydrogenated siliconfilm or body using a hydrogen plasma, the amorphous hydrogenated siliconfilm or body being transformed into a microcrystalline hydrogenatedsilicon film, and repeating the steps if necessary characterized in thatthe coating or the treatment is carried out with a continuous flow ofthe coating gases or the treatment gases and using pulsedelectromagnetic radiation which excites the plasma.

[0115] With the aid of the method of U.S. Pat. No. 5,643,638, layershaving a composition gradient and/or structure gradient can be produced.Via these gradients, specific physical and/or chemical characteristicscan be varied in a targeted manner. These physical and/or chemicalcharacteristics include, for example: refractive index, hardness,internal stress, hydrophily or general wetting ability, module ofelasticity and the like. Gradient layers having constant composition butchangeable physical/chemical characteristics can be produced. An exampleof this is the production of a TiO₂ layer from TiCl₄+O₂. For theproduction of a TiO₂ layer having characteristics which come close tosolid material, a specific pulse amplitude and pulse duration arenecessary. By shortening the pulse duration, the TiO₂ layer becomesincreasingly porous in the direction of growth and the refractive index(and hardness) is lower even though the layer composition is constantover the layer thickness. Thus, said layer gradient is possibly in thelayer composition. In one embodiment said gradient in said layer isdefined by a transition from organic to inorganic. In one embodimentsaid gradient is a gradient in the structure of said layer. In oneembodiment said layer gradient is varied so as to provide a gradient ofat least one of the following characteristics: hardness, wettability,refractive index, absorption, porosity, crystal structure, modulus ofelasticity and electrical conductivity.

[0116] In one embodiment of the invention use may possibly be made of3-chloropropyltrimethoxysilane (United Chemical Technologies Inc.C-3300) as the chlorosilane.

[0117] In one possible embodiment the chlorosilane may possiblycomprises silicon chloride hydride (Cl₂H₂Si).

[0118] The entry in the Merck Index relating to silane, on page 8567, ishereby incorporated by reference as if set forth in its entirety herein(MERCK INDEX, Thirteenth Edition, copyright 2001 by Merck & Co., Inc,IBN Number 0911910-13-1).

[0119] In one embodiment of the invention the conductive film may be atin oxide (SnO) film.

[0120] The components disclosed in the various publications, disclosedor incorporated by reference herein, may be used in the embodiments ofthe present invention, as well as equivalents thereof.

[0121] The appended drawings in their entirety, including alldimensions, proportions and/or shapes in at least one embodiment of theinvention, are accurate and are hereby included by reference into thisspecification.

[0122] All, or substantially all, of the components and methods of thevarious embodiments may be used with at least one embodiment or all ofthe embodiments, if more than one embodiment is described herein.

[0123] All of the patents, patent applications and publications recitedherein, and in the Declaration attached hereto, are hereby incorporatedby reference as if set forth in their entirety herein.

[0124] The following patents, patent applications, or patentpublications, or other documents which were cited in the German PatentOffice, namely: Federal Republic of Germany Patent No. 44 45 427(corresponding to U.S. Pat. No. 5,643,638); U.S. Pat. No. 5,693,957,U.S. Pat. No. 5,618,758, U.S. Pat. No. 5,344,796, U.S. Pat. No.5,334,423, U.S. Pat. No. 5,204,272, U.S. Pat. No. 4,891,330, and U.S.Pat. No. 4,762,803; European Patent No. 05 71 632 (corresponding to U.S.Pat. No. 5,387,542); International Patent Publications: No. WO 97 24 769(corresponding to U.S. Pat. No. 6,309,906), No. WO 93 13 553(corresponding to U.S. Pat. No. 5,231,048), and No. WO 93 10 555(corresponding to U.S. Pat. No. 5,387,542); and documents: APPL. PHYS.LETTERS, Volume 56, 1990, pages 533 to 535, APPL. PHYS. LETTERS, Volume60, 1992, pages 2874 to 2876, J. APPL. PHYS., Volume 31, 1992, pages1948 to 1952, SOLAR ENERGY MATERIALS AND SOLAR CELLS, Volume 34, 1994,pages 509 to 515, MATERIAL RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS,Volume 452, 1997, pages 737 ff., and J. OF THE CERAMIC SOCIETY OF JAPAN,Volume 99, 1991, pages 894-902, are hereby incorporate as if set forthin their entirety herein.

[0125] The following patents, patent applications, or patentpublications, which were cited in the PCT Search Report dated Dec. 20,2000 (date of mailing), namely: EP 0 919 643 (corresponding to U.S. Pat.No. 6,100,466); FR 2,743,193 (corresponding to U.S. Pat. No. 6,309,906);EP 0 526 779 (corresponding to U.S. Pat. No. 5,242,530); and U.S. Pat.No. 4,804,605, are hereby incorporated by reference as if set forth intheir entirety herein.

[0126] The following patents, referred to above, namely, U.S. Pat. No.5,204,272 issued to Guha, et al. on Apr. 20, 1993 and entitled,“Semiconductor device and microwave process for its manufacture”; U.S.Pat. No. 5,231,048 issued to Guha, et al. on Jul. 27, 1993 and entitled,“Microwave energized deposition process wherein the deposition iscarried out at a pressure less than the pressure of the minimum point ofthe deposition system's Paschen curve”; U.S. Pat. No. 5,334,423 issuedto Guha, et al. on Aug. 2, 1994 and entitled, “Microwave energizedprocess for the preparation of high quality semiconductor material”;U.S. Pat. No. 5,344,796 issued to Shin, et al. on Sep. 6, 1994 andentitled, “Method of making polycrystalline silicon thin film”; U.S.Pat. No. 5,387,542 issued to Yamamoto, et al. on Feb. 7, 1995 andentitled, “Polycrystalline silicon thin film and low temperaturefabrication method thereof”; U.S. Pat. No. 5,470,619 issued to Ahn, etal. on Nov. 28, 1995 and entitled, “Method of the production ofpolycrystalline silicon thin films”; U.S. Pat. No. 5,486,237 issued toSano, et al. on Jan. 23, 1996 and entitled, “Polysilicon thin film andmethod of preparing polysilicon thin film and photovoltaic elementcontaining same”; U.S. Pat. No. 5,618,758 issued to Tomita, et al. onApr. 8, 1997 and entitled, “Method for forming a thin semiconductor filmand a plasma CVD apparatus to be used in the method”; U.S. Pat. No.5,643,638 issued to Otto, et al. on Jul. 1, 1997 and entitled, “PlasmaCVD method of producing a gradient layer”; U.S. Pat. No. 5,693,957issued to Sano, et al. on Dec. 2, 1997 and entitled, “Photovoltaicelement and method of manufacturing the same”; and U.S. Pat. No.6,309,906 issued to Meier, et al. on Oct. 30, 2001 and entitled,“Photovoltaic cell and method of producing that cell”; are herebyincorporated by reference as if set forth in their entirety herein.

[0127] The following documents are to be incorporated, namely: Asano,A.; APPL. PHYS. LETT. 56 (1990) 533; Jin Jang; Sung Ok Koh; Tae Gon Kim;Sung Chul Kim, APPL. PHYS. LETT. 60 (1992) 2874; Otobe, M.; Oda, S.;JPN. J. APPL. PHYS. 31 (1992) 1948; Kyu Chang Park, Sung Yi Kim; MinPark; Jung Mok Jun; Kyung Ha Lee; Jin Jang; SOLAR ENERGY MATERIALS ANDSOLAR CELLS, Vol. 34 (1994), 509; Hapke, P.; Carius, R.; Finger, F.;Lambertz, A.; Vetterl, O; Wagner H. MATERIAL RESEARCH SOCIETY SYMPOSIUMPROCEEDINGS, Vol. 452; (1997), 737.

[0128] The corresponding foreign and international patent publicationapplications, namely, Federal Republic of Germany Patent Application No.1999 35 046.9-33 filed on Jul. 26, 1999, having the title,“PLASMA-CVD-VERFAHREN UND VORRICHTUNG ZUR HERSTELLUNG EINERMIKROKRISTALLINEN Si:H-SCHICHT AUF EINEM SUBSTRAT”, having the inventorsManfred LOHMEYER, Stefan BAUER, Burkhard DANIELZIK, Wolfgang MÖHL, andNina FREITAG; DE-OS 199 35 046, published on Mar. 1, 2001; and FederalRepublic of Germany Patent No. 199 35 046 C2, issued on Jul. 12, 2001;and International Application No. PCT/EP/00/07082, filed on Jul. 25,2000, having inventors Manfred LOHMEYER, Stefan BAUER, BurkhardDANIELZIK, Wolfgang MÖHL, and Nina FREITAG, as well as their publishedequivalents, and other equivalents or corresponding applications, ifany, in corresponding cases in the Federal Republic of Germany andelsewhere, and the references and documents cited in any of thedocuments cited herein, such as the patents, patent applications andpublications, are hereby incorporated by reference as if set forth intheir entirety herein.

[0129] The following applications, assigned to the Assignee hereof, andrelating to substrate glass material compositions which may possibly beused or adapted for use in at least one possible embodiment of theinvention, are to be incorporated by reference as if set forth in theirentirety herein: U.S. patent application Ser. No. 09/758,919 filed onJan. 11, 2001, having inventors Dr. Ulrich PEUCHERT and Dr. Peter BRIX,having Attorney Docket No. NHL-SCT-18 US, and having the title,“Alkali-free aluminoborosilicate glass, and uses thereof”; U.S. patentapplication Ser. No. 09/758,952 filed on Jan. 11, 2001, having inventorsDr. Ulrich PEUCHERT and Dr. Peter BRIX, having Attorney Docket No.NHL-SCT-19 US, and having the title, “Alkali-free aluminoborosilicateglass, and uses thereof”; U.S. patent application Ser. No. 09/758,946filed on Jan. 11, 2001, having inventors Dr. Ulrich PEUCHERT and Dr.Peter BRIX, having Attorney Docket No. NHL-SCT-20 US, and having thetitle, “Alkali-free aluminoborosilicate glass, and uses thereof”; U.S.patent application Ser. No. 09/758,903 filed on Jan. 11, 2001, havinginventors Dr. Ulrich PEUCHERT and Dr. Peter BRIX, having Attorney DocketNo. NHL-SCT-21 US, and having the title, “Alkali-freealuminoborosilicate glass, and uses thereof”. The foregoing applicationsare hereby incorporated by reference as if set forth in their entiretyherein.

[0130] Some examples of thin-film solar cells, features of which maypossibly be used or adapted for use in at least one possible embodimentof the invention may be found in the following U.S. Pat. No. 4,064,521,issued to inventor Carlson on Dec. 20, 1977 and entitled, “Semiconductordevice having a body of amorphous silicon”; U.S. Pat. No. 4,338,482,issued to inventor Gordon on Jul. 6, 1982 and entitled, “Photovoltaiccell”; U.S. Pat. No. 4,433,202, issued to inventors Maruyama, et al. onFeb. 21, 1984 and entitled, “Thin film solar cell”; U.S. Pat. No.4,500,743, issued to inventors Hayashi et al. on Feb. 19, 1985 andentitled, “Amorphous semiconductor solar cell having a grainedtransparent electrode”; U.S. Pat. No. 4,609,770, issued to inventorsNishiura et al. on Sep. 2, 1986 and entitled, “Thin-film solar cellarray; U.S. Pat. No. 4,749,588, issued to inventors Fukuda et al. onJun. 7, 1988 and entitled, “Process for producing hydrogenated amorphoussilicon thin film and a solar cell”; U.S. Pat. No. 4,891,330, issued toinventors Guba et al. on Jan. 2, 1990 and entitled, “Method offabricating N-type and P-type microcrystalline semiconductor alloymaterial including band gap widening elements”; U.S. Pat. No. 4,948,740,issued to inventor Plaettner on Aug. 14, 1990 and entitled, “Method forthe integrated series-interconnection of thick-film solar cells andmethod for the manufacture of tandem solar cells”; U.S. Pat. No.5,055,141, issued to inventors Arya et al. on Oct. 8, 1991 and entitled,“Enhancement of short-circuit current by use of wide bandgap N-layers inP-I-N amorphous silicon photovoltaic cells”; U.S. Pat. No. 5,482,570,issued to inventors Saurer et al. on Jan. 9, 1996 and entitled,“Photovoltaic cell”; U.S. Pat. No. 5,828,117, issued to inventors Kondoet al. on Oct. 27, 1998 and entitled, “Thin-film solar cell”; U.S. Pat.No. 5,853,498, issued to inventors Beneking et al. on Dec. 29, 1998 andentitled, “Thin film solar cell”; and U.S. Pat. No. 6,124,545, issued toinventors Bauer et al. on Sep. 26, 2000 and entitled, “Thin film solarcell”. The foregoing patents are hereby incorporated by reference as ifset forth in their entirety herein

[0131] Some examples of microcrystalline hydrogenated silicon inthin-film solar cells, features of which may possibly be used or adaptedfor use in at least one possible embodiment of the invention may befound in the following U.S. Pat. No. 4,907,052, issued to inventorsTakada et al. on Mar. 6, 1990 and entitled, “Semiconductor tandem solarcells with metal silicide barrier”; U.S. Pat. No. 4,995,341, issued toinventor Matsuyama on Feb. 26, 1991 and entitled, “Microwave plasma CVDapparatus for the formation of a large-area functional deposited film”;U.S. Pat. No. 5,055,141, issued to inventors Arya et al. on Oct. 8, 1991and entitled, “Enhancement of short-circuit current by use of widebandgap N-layers in P-I-N amorphous silicon photovoltaic cells”; U.S.Pat. No. 5,696,349, issued to inventor Nakata on Nov. 11, 1997 andentitled, “Fabrication of a thin film transistor and production of aliquid crystal display apparatus”; and U.S. Pat. No. 6,072,117, issuedto inventors Matsuyama et al. on Jun. 6, 2000 and entitled,“Photovoltaic device provided with an opaque substrate having a specificirregular surface structure”. The foregoing patents are herebyincorporated by reference as if set forth in their entirety herein.

[0132] Some examples of substrate materials for use in thin-film solarcells, features of which may possibly be used or adapted for use in atleast one possible embodiment of the invention may be found in thefollowing U.S. Pat. No. 4,873,118, issued to inventors Elias et al. onOct. 10, 1989 and entitled, “Oxygen glow treating of ZnO electrode forthin film silicon solar cell”; U.S. Pat. No. 5,264,376, issued toinventors Abbott et al. on Nov. 23, 1993 and entitled, “Method of makinga thin film solar cell”; U.S. Pat. No. 5,415,700, issued to inventorsArthur et al. on May 16, 1995 and entitled, “Concrete solar cell”; U.S.Pat. No. 5,800,631, issued to inventors Yamada et al. on Sep. 1, 1998and entitled, “Solar cell module having a specific back side coveringmaterial and a process for the production of said solar cell module”;U.S. Pat. No. 5,964,962, issued to inventors Sannomiya et al. on Oct.12, 1999 and entitled, “Substrate for solar cell and method forproducing the same; substrate treatment apparatus; and thin film solarcell and method for producing the same”; and U.S. Pat. No. 6,331,673,issued to inventors Kataoka et al. on Dec. 18, 2001 and entitled, “Solarcell module having a surface side covering material with specificnonwoven glass fiber member”. The foregoing patents are herebyincorporated by reference as if set forth in their entirety herein.

[0133] Some examples of thin-film transistors, features of which maypossibly be used or adapted for use in at least one possible embodimentof the invention may be found in the following U.S. Pat. No. 6,258,638,issued to inventors Tanabe et al. on Jul. 10, 2001 and entitled, “Methodof manufacturing thin film transistor”; U.S. Pat. No. 6,277,679, issuedto inventor Ohtani on Aug. 21, 2001 and entitled, “Method ofmanufacturing thin film transistor”; U.S. Pat. No. 6,281,055, issued toinventor Yang on Aug. 28, 2001 and entitled, “Method of fabricating athin film transistor”; U.S. Pat. No. 6,288,413, issued to inventorsKamiura et al. on Sep. 11, 2001 and entitled, “Thin film transistor andmethod for producing same”; U.S. Pat. No. 6,300,175, issued to inventorMoon on Oct. 9, 2001 and entitled, “Method for fabricating thin filmtransistor”; U.S. Pat. No. 6,300,659, issued to inventors Zhang et al.on Oct. 9, 2001 and entitled, “Thin-film transistor and fabricationmethod for same”; U.S. Pat. No. 6,312,992, issued to inventor Cho onNov. 6, 2001 and entitled, “Thin film transistor and method forfabricating the same”; U.S. Pat. No. 6,316,294, issued to inventors Yoonet al. on Nov. 13, 2001 and entitled, “Thin film transistor and afabricating method thereof”; and U.S. Pat. No. 6,316,295, issued toinventors Jang et al. on Nov. 13, 2001 and entitled, “Thin filmtransistor and its fabrication”. The foregoing patents are herebyincorporated by reference as if set forth in their entirety herein.

[0134] Some examples of hydrogenated silicon in thin-film transistors,features of which may possibly be used or adapted for use in at leastone possible embodiment of the invention may be found in the followingU.S. Pat. No. 5,093,703, issued to inventors Minami et al. on Mar. 3,1992 and entitled, “Thin film transistor with 10-15% hydrogen content”;U.S. Pat. No. 5,153,690, issued to inventors Tsukada et al. on Oct. 6,1992 and entitled, “Thin-film device”; U.S. Pat. No. 5,266,825, issuedto inventors Tsukuda et al. on Nov. 30, 1993 and entitled, “Thin-filmdevice”; U.S. Pat. No. 5,326,712, issued to inventor Bae on Jul. 5, 1994and entitled, “Method for Manufacturing a thin film transistor”; U.S.Pat. No. 5,397,718, issued to inventors Furuta et al. on Mar. 14, 1995and entitled, “Method of manufacturing thin film transistor”; U.S. Pat.No. 5,627,089, issued to inventors Kim et al. on May 6, 1997 andentitled, “Method for fabricating a thin film transistor using APCVD”;U.S. Pat. No. 5,648,276, issued to inventors Hara et al. on Jul. 15,1997 and entitled, “Method and apparatus for fabricating a thin filmsemiconductor device”; U.S. Pat. No. 5,696,387, issued to inventors Choiet al. on Dec. 9, 1997 and entitled, “Thin film transistor in a liquidcrystal display having a microcrystalline and amorphous active layerswith an intrinsic semiconductor layer attached to same”; U.S. Pat. No.5,824,572, issued to inventors Fukui et al. on Oct. 20, 1998 andentitled, “method of manufacturing thin film transistor”; U.S. Pat. No.5,834,071, issued to inventor Lin on Nov. 10, 1998 and entitled, “Methodfor forming a thin film transistor”; U.S. Pat. No. 6,107,641, issued toinventors Mei et al. on Aug. 22, 2000 and entitled, “Thin filmtransistor with reduced parasitic capacitance and reduced feedthroughvoltage”; U.S. Pat. No. 6,207,472, issued to inventors Callegari et al.on Mar. 27, 2001 and entitled, “Low temperature thin film transistorfabrication”; U.S. Pat. No. 6,235,559, issued to inventor Kuo on May 22,2001 and entitled, “Thin film transistor with carbonaceous gatedielectric”; and U.S. Pat. No. 6,258,638, issued to inventors Tanabe etal. on Jul. 10, 2001 and entitled, “Method of manufacturing thin filmtransistor”. The foregoing patents are hereby incorporated by referenceas if set forth in their entirety herein.

[0135] Some examples of substrate materials for thin-film transistors,features of which may possibly be used or adapted for use in at leastone possible embodiment of the invention may be found in the followingU.S. Pat. No. 4,335,161, issued to inventor Lao on Jun. 15, 1981 andentitled, “Thin film transistors, thin film transistor arrays, and aprocess for preparing the same”; U.S. Pat. No. 4,404,731, issued toinventor Poleshuk on Sep. 20, 1983 and entitled, “Method of forming athin film transistor”; U.S. Pat. No. 5,306,651, issued to inventorsMasumo et al. on Apr. 26, 1994 and entitled, “Process for preparing apolycrystalline semiconductor thin film transistor”; U.S. Pat. No.5,330,941, issued to inventors Yaba et al. on Jul. 19, 1994 andentitled, “Quartz glass substrate for polysilicon thin film transistorliquid crystal display”; U.S. Pat. No. 5,665,611, issued to inventorsSandhu et al. on Sep. 9, 1997 and entitled, “Method of forming a thinfilm transistor using fluorine passivation”; U.S. Pat. No. 5,811,323,issued to inventors Miyasaka et al. on Sep. 22, 1998 and entitled,“Process for fabricating a thin film transistor”; U.S. Pat. No.5,834,345, issued to inventor Shimizu on Nov. 10, 1998 and entitled,“Method of fabricating field effect think film transistor”; U.S. Pat.No. 5,936,259, issued to inventors Katz et al. on Aug. 10, 1999 andentitled, “Thin film transistor and organic semiconductor materialthereof”; U.S. Pat. No. 6,207,472, issued to inventors Callegari et al.on Mar. 27, 2001 and entitled, “Low temperature thin film transistorfabrication”; and U.S. Pat. No. 6,329,226, issued to inventors Jones etal. on Dec. 11, 2001 and entitled, “Method for fabricating a thin-filmtransistor”. The foregoing patents are hereby incorporated by referenceas if set forth in their entirety herein.

[0136] Some examples of microwave plasma chemical vapor depositionapparatus, features of which may possibly be used or adapted for use inat least one possible embodiment of the invention may be found in thefollowing U.S. Pat. No. 4,265,730, issued to inventors Hirose et al. onMay 5, 1981 and entitled, “Surface treating apparatus utilizing plasmagenerated by microwave discharge”; U.S. Pat. No. 4,715,927, issued toinventors Johncock et al. on Dec. 29, 1987 and entitled, “Improvedmethod of making a photoconductive member”; U.S. Pat. No. 4,785,763,issued to inventor Saitoh on Nov. 22, 1988 and entitled, “Apparatus forthe formation of a functional deposited film using microwave plasmachemical vapor deposition process”; U.S. Pat. No. 4,836,140, issued toinventor Koji on Jun. 6, 1989 and entitled, “Photo-CVD apparatus”; U.S.Pat. No. 4,866,346, issued to inventors Gaudreau on Sep. 12, 1989 andentitled, “Microwave plasma generator”; U.S. Pat. No. 4,995,341, issuedto inventor Matsuyama on Feb. 26, 1991 and entitled, “Microwave plasmaCVD apparatus for the formation of a large-area functional depositedfilm”; U.S. Pat. No. 5,232,507, issued to inventors Ohtoshi et al. onAug. 3, 1993 and entitled, “Apparatus for forming deposited films withmicrowave plasma CVD method”; U.S. Pat. No. 5,443,645, issued toinventors Otoshi et al. on Aug. 22, 1995 and entitled, “Microwave plasmaCVD apparatus comprising coaxially aligned multiple gas pipe gas feedstructure”; U.S. Pat. No. 5,510,151, issued to inventors Matsuyama etal. on Apr. 23, 1996 and entitled, “Continuous film-forming processusing microwave energy in a moving substrate web functioning as asubstrate and plasma generating space”; U.S. Pat. No. 5,919,310, issuedto inventors Fujioka et al. on Jul. 6, 1999 and entitled, “Continuouslyfilm-forming apparatus provided with improved gas gate means”; U.S. Pat.No. 6,028,393, issued to inventors Izu et al. on Feb. 22, 2000 andentitled, “E-beam/microwave gas jet PECVD method and apparatus fordepositing and/or surface modification of thin film materials”; and U.S.Pat. No. 6,253,703, issued to inventors Echizen et al. on Jul. 3, 2001and entitled, “Microwave chemical vapor deposition apparatus”. Theforegoing patents are hereby incorporated by reference as if set forthin their entirety herein.

[0137] Some examples of making tin oxide films and doped tin oxidefilms, features of which may possibly be used or adapted for use in atleast one possible embodiment of the invention may be found in thefollowing U.S. Pat. No. 5,330,855, issued to inventors Semancik et al.on Jul. 19, 1994 and entitled, “Planar epitaxial films of SnO₂”; U.S.Pat. No. 5,397,920, issued to inventor Tran on Mar. 14, 1995 andentitled, “Light transmissive, electrically-conductive, oxide film andmethods of production”; U.S. Pat. No. 5,527,391, issued to inventorsEchizen et al. on Jun. 18, 1996 and entitled, “Method and apparatus forcontinuously forming functional deposited films with a large area by amicrowave plasma CVD method”; U.S. Pat. No. 5,830,530, issued toinventor Jones on Nov. 3, 1998 and entitled, “Chemical vapor depositionof tin oxide films”; U.S. Pat. No. 5,864,149, issued to inventorYamamori on Jan. 26, 1999 and entitled, “Staggered thin film transistorwith transparent electrodes and an improved ohmic contact structure”;U.S. Pat. No. 6,057,005, issued to inventor Nishimoto on May 2, 2000 andentitled, “Method of forming semiconductor thin film”; U.S. Pat. No.6,165,598, issued to inventor Nelson on Dec. 26, 2000 and entitled,“Color suppressed anti-reflective glass”; U.S. Pat. No. 6,271,053,issued to inventor Kondo on Aug. 7, 2001 and entitled, “Method ofmanufacturing a thin film solar battery module”; U.S. Pat. No.6,281,429, issued to inventors Takada et al. on Aug. 28, 2001 andentitled, “Photoelectric conversion element”; U.S. Pat. No. 6,294,722,issued to inventors Kondo et al. on Sep. 25, 2001 and entitled,“Integrated thin-film solar battery”; U.S. Pat. No. 6,300,556, issued toinventors Yamagishi et al. on Oct. 9, 2001 and entitled, “Solar cellmodule”. The foregoing patents are hereby incorporated by reference asif set forth in their entirety herein.

[0138] Some examples of making zinc oxide films and doped zinc oxidefilms, features of which may possibly be used or adapted for use in atleast one possible embodiment of the invention may be found in thefollowing U.S. Pat. No. 5,470,618, issued to inventors Ohara et al. onNov. 28, 1995 and entitled, “Method of making zinc-based transparentconductive film”; U.S. Pat. No. 5,578,501, issued to inventor Niwa onNov. 26, 1996 and entitled, “Method of manufacturing a solar cell byformation of a zinc oxide transparent conductive layer”; U.S. Pat. No.5,804,466, issued to inventors Arao et al. on Sep. 8, 1998 and entitled,“Process for production of zinc oxide thin film, and process forproduction of semiconductor device substrate and process for productionof photoelectric conversion device using the same film”; U.S. Pat. No.6,140,570, issued to inventor Kariya on Oct. 31, 2000 and entitled,“Photovoltaic element having a back side transparent and electricallyconductive layer with a light incident side surface region having aspecific cross section and a module comprising said photovoltaicelement”; U.S. Pat. No. 6,224,736, issued to inventor Miyamoto on May 1,2001 and entitled, “Apparatus and method for forming thin film of zincoxide”; U.S. Pat. No. 6,242,080, issued to inventor Kondo on Jun. 5,2001 and entitled, “Zinc oxide thin film and process for producing thefilm”; U.S. Pat. No. 6,071,561, issued to inventors Gordon et al. onJun. 6, 2000 and entitled, “Chemical vapor deposition of fluorine-dopedzinc oxide”; and U.S. Pat. No. 5,470,618, issued to inventors Ohara etal. on Nov. 28, 1995 and entitled, “Method of making zinc-basedtransparent conductive film”. The foregoing patents are herebyincorporated by reference as if set forth in their entirety herein.

[0139] Some examples of making indium-tin-oxide (ITO) films, features ofwhich may possibly be used or adapted for use in at least one possibleembodiment of the invention may be found in the following U.S. Pat. No.5,514,217, issued to inventors Niino et al. on May 7, 1996 and entitled,“Microwave plasma CVD apparatus with a deposition chamber having acircumferential wall comprising a curved moving substrate web and amicrowave application means having a specific dielectric member on theexterior thereof”; U.S. Pat. No. 5,527,396, issued to inventors Saitohet al. on Jun. 18, 1996 and entitled, “Deposited film formingapparatus”; U.S. Pat. No. 5,559,344, issued to inventor Kawachi on Sep.24, 1996 and entitled, “Thin-film semiconductor element, thin-filmsemiconductor device and methods of fabricating the same”; U.S. Pat. No.5,603,778, issued to inventor Sonoda on Feb. 18, 1997 and entitled,“Method of forming transparent conductive layer, photoelectricconversion device using the transparent conductive layer, andmanufacturing method for the photoelectric conversion device”; U.S. Pat.No. 5,804,466, issued to inventors Arao et al. on Sep. 8, 1998 andentitled, “Process for production of zinc oxide thin film, and processfor production of semiconductor device substrate and process forproduction of photoelectric conversion device using the same film”; U.S.Pat. No. 5,913,986, issued to inventor Matsuyama on Jun. 22, 1999 andentitled, “Photovoltaic element having a specific doped layer”; and U.S.Pat. No. 6,146,929, issued to inventors Oana et al. on Nov. 14, 2000 andentitled, “Method for manufacturing semiconductor device using multiplesteps continuously without exposing substrate to the atmosphere”. Theforegoing patents are hereby incorporated by reference as if set forthin their entirety herein.

[0140] Some examples of the deposition gases which may be used oradapted for use in at least one embodiment of the present invention maybe found in the following U.S. Pat. No. 4,605,941, issued to Ovshinsky,et al. on Aug. 12, 1986 and entitled, “Amorphous semiconductorsequivalent to crystalline semiconductors”; U.S. Pat. No. 4,676,967,issued to Breneman on Jun. 30, 1987 and entitled, “High purity silaneand silicon production”; U.S. Pat. No. 4,678,679, issued to Ovshinsky onJul. 7, 1987 and entitled, “Continuous deposition of activated processgases”; U.S. Pat. No. 4,818,495, issued to Iya on Apr. 4, 1989 andentitled, “Reactor for fluidized bed silane decomposition”; U.S. Pat.No. 5,380,372, issued to Campe, et al on Jan. 10, 1995 and entitled,“Solar cell and method for manufacture thereof”; U.S. Pat. No.6,040,022, issued to Chang, et al. on Mar. 21, 2000 and entitled, “PECVDof compounds of silicon from silane and nitrogen”; U.S. Pat. No.6,103,942, issued to Tsuo, et al. on Aug. 15, 2000 and entitled, “Methodof high purity silane preparation”; and U.S. Pat. No. 6,323,142, issuedto Yamazaki, et al. on Nov. 27, 2001 and entitled, “APCVD method offorming silicon oxide using an organic silane, oxidizing agent, and acatalyst-formed hydrogen radical”. The foregoing patents are herebyincorporated by reference as if set forth in their entirety herein.

[0141] Some examples of the treatment gases comprising a hydrogen plasmawhich may be used or adapted for use in at least one embodiment of theinvention may be found in the following U.S. Pat. No. 6,173,673, issuedto Golovato, et al. on Jan. 16, 2001 and entitled, “Method an apparatusfor insulating a high power RF electrode through which plasma dischargegases are injected into a processing chamber”; U.S. Pat. No. 6,200,412,issued to Kilgore, et al. on Mar. 13, 2001 and entitled, “Chemical vapordeposition system including dedicated cleaning gas injection”; U.S. Pat.No. 6,258,173, issued to Kirimura, et al. on Jul. 10, 2001 and entitled,“Film forming apparatus for forming a crystalline silicon film”; U.S.Pat. No. 6,296,735, issued to Marxer, et al. on Oct. 2, 2001 andentitled, “Plasma treatment apparatus and method for operation same”;U.S. Pat. No. 6,297,442, issued to Yagi, et al. on Oct. 2, 2001 andentitled, “Solar cell, self-power-supply display device using same, andprocess for producing solar cell”; and No. 6,287,944, issued to Hara, etal. on Sep. 11, 2001 and entitled, “Polycrystalline semiconductor deviceand its manufacture method”. The foregoing patents are herebyincorporated by reference as if set forth in their entirety herein.

[0142] All of the references and documents, cited in any of thedocuments cited herein, and the references they are in turn cited in arehereby incorporated by reference as if set forth in their entiretyherein. All of the documents cited herein, referred to in theimmediately preceding sentence, include all of the patents, patentapplications and publications cited anywhere in the present application.

[0143] All of the references included herein as aforesaid include thecorresponding equivalents published by the United States Patent andTrademark Office and elsewhere.

[0144] Although only a few exemplary embodiments of this invention havebeen described in detail above, those skilled in the art will readilyappreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of this invention as defined inthe following claims. In the claims, means-plus-function clauses areintended to cover the structures described herein as performing therecited function and not only structural equivalents but also equivalentstructures.

[0145] One feature of the invention resides broadly in a thin-film solarcell (18), comprising:

[0146] a transparent substrate (10) having a first surface configured toreceive incident light and a second surface opposite said first surface;

[0147] a first electrode (12) having a first surface and a secondsurface opposite said first surface;

[0148] said first electrode (12) comprising an electrically conductivelayer of a transparent conductive material;

[0149] a microcrystalline hydrogenated silicon semiconductor body (16);

[0150] said microcrystalline hydrogenated silicon semiconductor body(16) having a first surface and a second surface opposite said firstsurface;

[0151] said microcrystalline hydrogenated silicon semiconductor body(16) being disposed with said first surface thereof on said secondsurface of said first electrode (12);

[0152] said microcrystalline hydrogenated silicon semiconductor body(16) originated from a continuous-gas-flow,pulsed-electromagnetic-radiation-excited plasma, plasma-enhancedchemical vapor deposited, continuous-gas-flow,pulsed-electromagnetic-radiation-excited,hydrogen-plasma-enhanced-treated amorphous hydrogenated silicon body;

[0153] said second surface of said first electrode (12) comprising asurface configured to accept said microcrystalline hydrogenated siliconsemiconductor body (16);

[0154] said microcrystalline hydrogenated silicon semiconductor body(16) comprising at least one semiconductor layer (13, 14, 15);

[0155] at least one of each said at least one semiconductor layer (13,14, 15) having a thickness of from about one tenth of a nanometer toabout fifty nanometers;

[0156] a second electrode (17) having a first surface and a secondsurface opposite said first surface;

[0157] said second electrode (17) being disposed with said first surfacethereof on said second surface of said microcrystalline hydrogenatedsilicon semiconductor body (16);

[0158] a first conductor element (20) connected to said first electrode(12); and

[0159] a second conductor element (22) connected to said secondelectrode (17);

[0160] said first conductor element (20) and said second conductorelement (22) being configured and disposed to lead electricity from saidsolar cell (18);

[0161] said substrate (10) having a predetermined heat stability;

[0162] said predetermined heat stability being sufficiently great topermit manufacture of a thin-film solar cell (18) and said predeterminedheat stability being sufficiently low to minimize cost.

[0163] Another feature of the invention resides broadly in the thin-filmsolar cell wherein:

[0164] said substrate (10) comprises one of: a glass, a glass ceramic,or a plastic.

[0165] Yet another feature of the invention resides broadly in thethin-film solar cell wherein:

[0166] said transparent conductive material of said first electrode (12)comprises one of: an indium-tin-oxide, a doped tin dioxide film, or adoped zinc oxide film.

[0167] Still another feature of the invention resides broadly in thethin-film solar cell wherein:

[0168] said amorphous hydrogenated silicon body comprises a plurality oflayers;

[0169] said plurality of layers comprises from one to fifty amorphoushydrogenated silicon layers deposited on said second surface of saidsubstrate;

[0170] at least the first amorphous hydrogenated silicon layer comprisesa concentration of inherent microcrystalline hydrogenated silicon; saidfirst amorphous hydrogenated silicon layer having a first surfacedisposed on said second surface of said substrate, and said firstamorphous hydrogenated silicon layer having a second surface oppositesaid first surface; said concentration of inherent microcrystallinehydrogenated silicon increasing from said first surface of said firstlayer to said second surface of said first layer;

[0171] said microcrystalline hydrogenated silicon body has a thicknessof up to about five thousand nanometers;

[0172] at least one microcrystalline hydrogenated silicon layer has aconductivity in the range of from about one tenth microsiemens percentimeter to about ten siemens per centimeter.

[0173] A further feature of the invention resides broadly in a thin-filmtransistor, comprising:

[0174] a substrate (30) having a first surface and a second surfaceopposite said first surface;

[0175] a microcrystalline hydrogenated silicon semiconductor body (32);

[0176] said microcrystalline hydrogenated silicon semiconductor body(32) having a first surface and a second surface opposite said firstsurface;

[0177] said microcrystalline hydrogenated silicon semiconductor body(32) being disposed with said first surface thereof on said secondsurface of said substrate (30);

[0178] said microcrystalline hydrogenated silicon semiconductor body(32) originated from a continuous-gas-flow,pulsed-electromagnetic-radiation-excited plasma, plasma-enhancedchemical vapor deposited, continuous-gas-flow,pulsed-electromagnetic-radiation-excited,hydrogen-plasma-enhanced-treated amorphous hydrogenated silicon body;

[0179] said microcrystalline hydrogenated silicon semiconductor body(32) comprising at least one semiconductor layer;

[0180] at least one of each said at least one semiconductor layer havinga thickness of from about one tenth of a nanometer to about fiftynanometers;

[0181] said microcrystalline hydrogenated silicon semiconductor body(32) comprising a source layer (34) and a drain layer (36);

[0182] a plurality of insulating films (38, 40, 42) disposed on saidmicrocrystalline hydrogenated silicon semiconductor body (32);

[0183] said plurality of insulating films (38, 40, 42) comprising afirst insulating film (38), a second insulating film (40), and a thirdinsulating film (42);

[0184] a gate electrode (44) disposed on said first insulating film(38);

[0185] a source electrode (46) disposed on said second insulating film(40);

[0186] a drain electrode (48) disposed on said third insulating film(42);

[0187] said substrate (30) comprising a predetermined heat stability;

[0188] said predetermined heat stability being sufficiently great topermit manufacture of a thin-film transistor and said predetermined heatstability being sufficiently low to minimize cost.

[0189] Another feature of the invention resides broadly in the thin-filmtransistor wherein:

[0190] said substrate (30) comprises one of: a glass, a glass ceramic,or a plastic.

[0191] Yet another feature of the invention resides broadly in thethin-film transistor wherein:

[0192] said amorphous hydrogenated silicon body comprises a plurality oflayers;

[0193] said plurality of layers comprises from one to fifty amorphoushydrogenated silicon layers deposited on said second surface of saidsubstrate;

[0194] at least the first amorphous hydrogenated silicon layer comprisesa concentration of inherent microcrystalline hydrogenated silicon; saidfirst amorphous hydrogenated silicon layer having a first surfacedisposed on said second surface of said substrate, and said firstamorphous hydrogenated silicon layer having a second surface oppositesaid first surface; said concentration of inherent microcrystallinehydrogenated silicon increasing from said first surface of said firstlayer to said second surface of said first layer;

[0195] said microcrystalline hydrogenated silicon body has a thicknessof up to about five thousand nanometers;

[0196] at least one microcrystalline hydrogenated silicon layer has aconductivity in the range of from about one tenth microsiemens percentimeter to about ten siemens per centimeter.

[0197] Still another feature of the invention resides broadly in aprocess for providing a microcrystalline hydrogenated siliconsemiconductor body on a substrate, such as, a substrate for a thin-filmsolar cell, or a substrate for a thin-film transistor, said processcomprising:

[0198] providing a substrate (10, 30), said substrate having a firstsurface and a second surface opposite said first surface;

[0199] flowing a plasma-enhanced chemical vapor deposition gas over saidsecond surface of said substrate to deposit a body of amorphoushydrogenated silicon on said second surface of said substrate;

[0200] flowing a plasma-enhanced, hydrogen-plasma containing conversiongas over said deposited body of amorphous hydrogenated silicon toconvert said deposited body of amorphous hydrogenated silicon into abody of microcrystalline hydrogenated silicon (16,32);

[0201] said flowing of said deposition gas and said flowing of saidconversion gas comprising at least one of: (a.), (b.), (c.), and (d.):

[0202] (a.) continuously flowing said plasma-enhanced chemical vapordeposition gas over said second surface of said substrate (10, 30) todeposit said body of amorphous hydrogenated silicon on said secondsurface of said substrate;

[0203] (b.) continuously flowing said plasma-enhanced, hydrogen-plasmacontaining conversion gas over said body of amorphous hydrogenatedsilicon to convert said deposited body of amorphous hydrogenated siliconinto a body of microcrystalline hydrogenated silicon (16, 32);

[0204] (c.) exposing said plasma-enhanced chemical vapor deposition gasto a pulsed electromagnetic radiation with a sufficient radiationintensity to excite said plasma contained in said plasma-enhancedchemical vapor deposition gas thus depositing said deposited body ofamorphous hydrogenated silicon on said second surface of said substrate;

[0205] (d.) exposing said plasma-enhanced, hydrogen-plasma conversiongas to a pulsed electromagnetic radiation with a sufficient radiationintensity to excite said plasma contained in said plasma-enhanced,hydrogen-plasma conversion gas to thus effectuate conversion of saidamorphous hydrogenated silicon body into said deposited body ofmicrocrystalline hydrogenated silicon (16, 32);

[0206] and said method further comprising:

[0207] attaching at least two electrode means to said body ofmicrocrystalline hydrogenated silicon and forming one of: a thin-filmsolar cell, or a thin-film transistor.

[0208] A further feature of the invention resides broadly in the processwherein:

[0209] said substrate (10, 30) comprises a predetermined heat stability;

[0210] said predetermined heat stability being sufficiently great topermit manufacture of a thin-film solar cell and said predetermined heatstability being sufficiently low to minimize cost.

[0211] Another feature of the invention resides broadly in the processwherein:

[0212] said depositing of said amorphous hydrogenated silicon comprisesdepositing a plurality of layers to form said body of amorphoushydrogenated silicon;

[0213] said plurality of layers comprises from one to fifty amorphoushydrogenated silicon layers deposited on said second surface of saidsubstrate (10, 30).

[0214] Yet another feature of the invention resides broadly in theprocess wherein:

[0215] at least the first amorphous hydrogenated silicon layer isdeposited to comprises a concentration of inherent microcrystallinehydrogenated silicon;

[0216] said first amorphous hydrogenated silicon layer having a firstsurface disposed on said second surface of said substrate, and saidfirst amorphous hydrogenated silicon layer having a second surfaceopposite said first surface;

[0217] said concentration of inherent microcrystalline hydrogenatedsilicon increasing from said first surface of said first layer to saidsecond surface of said first layer.

[0218] Still another feature of the invention resides broadly in theprocess wherein:

[0219] at least one amorphous hydrogenated silicon layer is depositedwith a thickness of from about one tenth of a nanometer to about fivenanometers.

[0220] A further feature of the invention resides broadly in the processaccording comprising:

[0221] applying said plasma-enhanced, hydrogen-plasma conversion gas fora period of one of: up to about ten seconds, and less than about thirtyseconds;

[0222] exposing said plasma to electromagnetic radiation for a period oftime equal to or greater than one tenth of a millisecond;

[0223] said pulsed electromagnetic radiation of said plasma comprisessequential pulses, with the period of time between two pulses is atleast two hundred milliseconds.

[0224] Another feature of the invention resides broadly in the processcomprising:

[0225] depositing a microcrystalline hydrogenated silicon body (16, 32)having a thickness of up to about five thousand nanometers.

[0226] Yet another feature of the invention resides broadly in theprocess wherein:

[0227] said electromagnetic radiation comprises a microwave radiation;

[0228] said microwave radiation having a frequency of about two andforty-five hundredths gigahertz;

[0229] said microwave radiation having a mean microwave power of fromabout one hundred and fifty milliwatts per square centimeter to aboutfifteen hundred milliwatts per square centimeter.

[0230] Still another feature of the invention resides broadly in theprocess wherein:

[0231] said deposition gas contains at least one Si-organic film-formingagent;

[0232] said deposition gas comprises one of: a silane, SiH₄, or achlorosilane;

[0233] said deposition gas additionally comprises hydrogen.

[0234] A further feature of the invention resides broadly in the processwherein:

[0235] at least said deposition gas has a pressure of from about onetenth millibar to about one millibar;

[0236] said deposition gas is evacuated and said conversion gas isintroduced within about ten milliseconds.

[0237] Another feature of the invention resides broadly in the processcomprising:

[0238] maintaining the substrate temperature during said depositing ofsaid amorphous hydrogenated silicon body and during said converting ofsaid amorphous hydrogenated silicon body into said microcrystallinesilicon body at a temperature of one of: not exceeding two hundreddegrees Celsius, approximately one hundred degrees Celsius, and fiftydegrees Celsius.

[0239] Yet another feature of the invention resides broadly in theprocess comprising:

[0240] setting a conductivity of one microcrystalline hydrogenatedsilicon layer to a value in the range of from about one tenthmicrosiemens per centimeter to about ten siemens per centimeter by theintroduction of doped atoms contained in said deposition gas.

[0241] Still another feature of the invention resides broadly in theprocess wherein:

[0242] said substrate (10, 30) comprises one of: a glass, a glassceramic, or a plastic.

[0243] One feature of the invention resides broadly in the processcomprising:

[0244] applying a transparent conductive film on said second surface ofsaid substrate;

[0245] said transparent conductive film comprises one of: anindium-tin-oxide, a doped tin dioxide film, or a doped zinc oxide film.

[0246] Another feature of the invention resides broadly in the processwherein:

[0247] said process comprises a deposition chamber (50) in which todeposit said amorphous hydrogenated body and to convert said amorphoushydrogenated silicon body into said microcrystalline hydrogenatedsilicon body;

[0248] said deposition chamber comprising inner surfaces;

[0249] said process comprising:

[0250] depositing at least one amorphous hydrogenated silicon layer onsaid inner surfaces of said deposition chamber prior to applying saidconversion gas to an amorphous hydrogenated silicon layer.

[0251] The details in the patents, patent applications and publicationsmay be considered to be incorporable, at applicant's option, into theclaims during prosecution as further limitations in the claims topatentably distinguish any amended claims from any applied prior art.

[0252] The invention as described hereinabove in the context of thepreferred embodiments is not to be taken as limited to all of theprovided details thereof, since modifications and variations thereof maybe made without departing from the spirit and scope of the invention.

What is claimed is:
 1. A thin-film solar cell, comprising: a transparentsubstrate having a first surface configured to receive incident lightand a second surface opposite said first surface; a first electrodehaving a first surface and a second surface opposite said first surface;said first electrode comprising an electrically conductive layer of atransparent conductive material; a microcrystalline hydrogenated siliconsemiconductor body; said microcrystalline hydrogenated siliconsemiconductor body having a first surface and a second surface oppositesaid first surface; said microcrystalline hydrogenated siliconsemiconductor body being disposed with said first surface thereof onsaid second surface of said first electrode; said microcrystallinehydrogenated silicon semiconductor body originated from acontinuous-gas-flow, pulsed-electromagnetic-radiation-excited plasma,plasma-enhanced chemical vapor deposited, continuous-gas-flow,pulsed-electromagnetic-radiation-excited,hydrogen-plasma-enhanced-treated amorphous hydrogenated silicon body;said second surface of said first electrode comprising a surfaceconfigured to accept said microcrystalline hydrogenated siliconsemiconductor body; said microcrystalline hydrogenated siliconsemiconductor body comprising at least one semiconductor layer; at leastone of each said at least one semiconductor layer having a thickness offrom about one tenth of a nanometer to about fifty nanometers; a secondelectrode having a first surface and a second surface opposite saidfirst surface; said second electrode being disposed with said firstsurface thereof on said second surface of said microcrystallinehydrogenated silicon semiconductor body; a first conductor elementconnected to said first electrode; and a second conductor elementconnected to said second electrode; said first conductor element andsaid second conductor element being configured and disposed to leadelectricity from said solar cell; said substrate having a predeterminedheat stability; said predetermined heat stability being sufficientlygreat to permit manufacture of a thin-film solar cell and saidpredetermined heat stability being sufficiently low to minimize cost. 2.The thin-film solar cell according to claim 1, wherein: said substratecomprises one of: a glass, a glass ceramic, or a plastic.
 3. Thethin-film solar cell according to claim 2, wherein: said transparentconductive material of said first electrode (12) comprises one of: anindium-tin-oxide, a doped tin dioxide film, or a doped zinc oxide film.4. The thin-film solar cell according to claim 1, wherein: saidamorphous hydrogenated silicon body comprises a plurality of layers;said plurality of layers comprises from one to fifty amorphoushydrogenated silicon layers deposited on said second surface of saidsubstrate; at least the first amorphous hydrogenated silicon layercomprises a concentration of inherent microcrystalline hydrogenatedsilicon; said first amorphous hydrogenated silicon layer having a firstsurface disposed on said second surface of said substrate, and saidfirst amorphous hydrogenated silicon layer having a second surfaceopposite said first surface; said concentration of inherentmicrocrystalline hydrogenated silicon increasing from said first surfaceof said first layer to said second surface of said first layer; saidmicrocrystalline hydrogenated silicon body has a thickness of up toabout five thousand nanometers; at least one microcrystallinehydrogenated silicon layer has a conductivity in the range of from aboutone tenth microsiemens per centimeter to about ten siemens percentimeter.
 5. A thin-film transistor, comprising: a substrate having afirst surface and a second surface opposite said first surface; amicrocrystalline hydrogenated silicon semiconductor body; saidmicrocrystalline hydrogenated silicon semiconductor body having a firstsurface and a second surface opposite said first surface; saidmicrocrystalline hydrogenated silicon semiconductor body being disposedwith said first surface thereof on said second surface of saidsubstrate; said microcrystalline hydrogenated silicon semiconductor bodyoriginated from a continuous-gas-flow,pulsed-electromagnetic-radiation-excited plasma, plasma-enhancedchemical vapor deposited, continuous-gas-flow,pulsed-electromagnetic-radiation-excited,hydrogen-plasma-enhanced-treated amorphous hydrogenated silicon body;said microcrystalline hydrogenated silicon semiconductor body comprisingat least one semiconductor layer; at least one of each said at least onesemiconductor layer having a thickness of from about one tenth of ananometer to about fifty nanometers; said microcrystalline hydrogenatedsilicon semiconductor body comprising a source layer and a drain layer;a plurality of insulating films disposed on said microcrystallinehydrogenated silicon semiconductor body; said plurality of insulatingfilms comprising a first insulating film, a second insulating film, anda third insulating film; a gate electrode disposed on said firstinsulating film; a source electrode disposed on said second insulatingfilm; a drain electrode disposed on said third insulating film; saidsubstrate comprising a predetermined heat stability; said predeterminedheat stability being sufficiently great to permit manufacture of athin-film transistor and said predetermined heat stability beingsufficiently low to minimize cost.
 6. The thin-film transistor accordingto claim 5, wherein: said substrate comprises one of: a glass, a glassceramic, or a plastic.
 7. The thin-film transistor according to claim 5,wherein: said amorphous hydrogenated silicon body comprises a pluralityof layers; said plurality of layers comprises from one to fiftyamorphous hydrogenated silicon layers deposited on said second surfaceof said substrate; at least the first amorphous hydrogenated siliconlayer comprises a concentration of inherent microcrystallinehydrogenated silicon; said first amorphous hydrogenated silicon layerhaving a first surface disposed on said second surface of saidsubstrate, and said first amorphous hydrogenated silicon layer having asecond surface opposite said first surface; said concentration ofinherent microcrystalline hydrogenated silicon increasing from saidfirst surface of said first layer to said second surface of said firstlayer; said microcrystalline hydrogenated silicon body has a thicknessof up to about five thousand nanometers; at least one microcrystallinehydrogenated silicon layer has a conductivity in the range of from aboutone tenth microsiemens per centimeter to about ten siemens percentimeter.
 8. A process for providing a microcrystalline hydrogenatedsilicon semiconductor body on a substrate, such as, a substrate for athin-film solar cell, or a substrate for a thin-film transistor, saidprocess comprising: providing a substrate, said substrate having a firstsurface and a second surface opposite said first surface; flowing aplasma-enhanced chemical vapor deposition gas over said second surfaceof said substrate to deposit a body of amorphous hydrogenated silicon onsaid second surface of said substrate; flowing a plasma-enhanced,hydrogen-plasma containing conversion gas over said deposited body ofamorphous hydrogenated silicon to convert said deposited body ofamorphous hydrogenated silicon into a body of microcrystallinehydrogenated silicon; said flowing of said deposition gas and saidflowing of said conversion gas comprising at least one of: (a.), (b.),(c.), and (d.): (a.) continuously flowing said plasma-enhanced chemicalvapor deposition gas over said second surface of said substrate todeposit said body of amorphous hydrogenated silicon on said secondsurface of said substrate; (b.) continuously flowing saidplasma-enhanced, hydrogen-plasma containing conversion gas over saidbody of amorphous hydrogenated silicon to convert said deposited body ofamorphous hydrogenated silicon into a body of microcrystallinehydrogenated silicon; (c.) exposing said plasma-enhanced chemical vapordeposition gas to a pulsed electromagnetic radiation with a sufficientradiation intensity to excite said plasma contained in saidplasma-enhanced chemical vapor deposition gas thus depositing saiddeposited body of amorphous hydrogenated silicon on said second surfaceof said substrate; (d.) exposing said plasma-enhanced, hydrogen-plasmaconversion gas to a pulsed electromagnetic radiation with a sufficientradiation intensity to excite said plasma contained in saidplasma-enhanced, hydrogen-plasma conversion gas to thus effectuateconversion of said amorphous hydrogenated silicon body into saiddeposited body of microcrystalline hydrogenated silicon; and said methodfurther comprising: attaching at least two electrode means to said bodyof microcrystalline hydrogenated silicon and forming one of: a thin-filmsolar cell, or a thin-film transistor.
 9. The process according to claim8, wherein: said substrate comprises a predetermined heat stability;said predetermined heat stability being sufficiently great to permitmanufacture of a thin-film solar cell and said predetermined heatstability being sufficiently low to minimize cost.
 10. The processaccording to claim 9, wherein: said depositing of said amorphoushydrogenated silicon comprises depositing a plurality of layers to formsaid body of amorphous hydrogenated silicon; said plurality of layerscomprises from one to fifty amorphous hydrogenated silicon layersdeposited on said second surface of said substrate.
 11. The processaccording to claim 10, wherein: at least the first amorphoushydrogenated silicon layer is deposited to comprises a concentration ofinherent microcrystalline hydrogenated silicon; said first amorphoushydrogenated silicon layer having a first surface disposed on saidsecond surface of said substrate, and said first amorphous hydrogenatedsilicon layer having a second surface opposite said first surface; saidconcentration of inherent microcrystalline hydrogenated siliconincreasing from said first surface of said first layer to said secondsurface of said first layer.
 12. The process according to claim 11,wherein: at least one amorphous hydrogenated silicon layer is depositedwith a thickness of from about one tenth of a nanometer to about fivenanometers.
 13. The process according to claim 12 comprising: applyingsaid plasma-enhanced, hydrogen-plasma conversion gas for a period of oneof: up to about ten seconds, and less than about thirty seconds;exposing said plasma to electromagnetic radiation for a period of timeequal to or greater than one tenth of a millisecond; said pulsedelectromagnetic radiation of said plasma comprises sequential pulses,with the period of time between two pulses is at least two hundredmilliseconds.
 14. The process according to claim 13 comprising:depositing a microcrystalline hydrogenated silicon body having athickness of up to about five thousand nanometers.
 15. The processaccording to claim 14, wherein: said electromagnetic radiation comprisesa microwave radiation; said microwave radiation having a frequency ofabout two and forty-five hundredths gigahertz; said microwave radiationhaving a mean microwave power of from about one hundred and fiftymilliwatts per square centimeter to about fifteen hundred milliwatts persquare centimeter.
 16. The process according to claim 15, wherein: saiddeposition gas contains at least one Si-organic film-forming agent; saiddeposition gas comprises one of: a silane, SiH₄, or a chlorosilane; saiddeposition gas additionally comprises hydrogen.
 17. The processaccording to claim 16, wherein: at least said deposition gas has apressure of from about one tenth millibar to about one millibar; saiddeposition gas is evacuated and said conversion gas is introduced withinabout ten milliseconds.
 18. The process according to claim 17comprising: maintaining the substrate temperature during said depositingof said amorphous hydrogenated silicon body and during said convertingof said amorphous hydrogenated silicon body into said microcrystallinesilicon body at a temperature of one of: not exceeding two hundreddegrees Celsius, approximately one hundred degrees Celsius, and fiftydegrees Celsius.
 19. The process according to claim 18 comprising:setting a conductivity of one microcrystalline hydrogenated siliconlayer to a value in the range of from about one tenth microsiemens percentimeter to about ten siemens per centimeter by the introduction ofdoped atoms contained in said deposition gas.
 20. The process accordingto claim 19, wherein: said substrate comprises one of: a glass, a glassceramic, or a plastic.
 21. The process according to claim 20 comprising:applying a transparent conductive film on said second surface of saidsubstrate; said transparent conductive film comprises one of: anindium-tin-oxide, a doped tin dioxide film, or a doped zinc oxide film.22. The process according to claim 21, wherein: said process comprises adeposition chamber in which to deposit said amorphous hydrogenated bodyand to convert said amorphous hydrogenated silicon body into saidmicrocrystalline hydrogenated silicon body; said deposition chambercomprising inner surfaces; said process comprising: depositing at leastone amorphous hydrogenated silicon layer on said inner surfaces of saiddeposition chamber prior to applying said conversion gas to an amorphoushydrogenated silicon layer.